The legal battle between DC Comics and the heirs to co-creator Jerry Siegel now looks like the prelude to a much larger battle over comic book IP: Jack Kirby's heirs now want their rights to, well, the entire Marvel Universe.

The heirs to Kirby, who co-created the Fantastic Four, the X-Men, the Avengers, Iron Man, Hulk, Thor and Captain America - and had a hand in creating Spider-Man, pretty much completing the set - have sent out 45 notices of copyright termination to companies including Marvel Entertainment, Disney, Paramount (distributors for Iron Man, Hulk and the next five Marvel movies), Sony (the studio behind the Spider-Man movies, 20th Century Fox (X-Men and Fantastic Four) and others, expressing intent to own copyright on Kirby's creations. The notices did not only involve comic books and movies; apparently, Hasbro and Universal also received notices, for the toy and theme park rights as well.

The Kirby estate is taking the claim seriously, hiring Marc Toberoff, the attorney who's been representing the Siegel estate in the recent Superman/Superboy lawsuits. While Marvel itself has offered no comment on the notices yet, Disney issued a statement saying, essentially, that it's not a big deal:

The notices involved are an attempt to terminate rights seven to 10 years from now, and involve claims that were fully considered in the acquisition.

Considering Kirby's importance to the creation of the core characters in the Marvel Universe, losing any control over the rights of his creations could be costly at best, devastating at worst, for Marvel and Disney. Considering that the Kirby estate was on good terms with Marvel as recently as 2006, when Marvel released a series based upon the previously unseen Kirby concept Galactic Bounty Hunters, expect some form of negotiations to be taking place sooner rather than later.